Oh yes. I have been using IAL for over a year now on my bettas. They take a few days to tan the water. I think a new leaf takes 2 days to sink. They float at first. But they can leech tannins as soon as a few hours depending on certain conditions.

I recommend them all the time because they help boost a bettas immune system. They are good to always have in the tank, there's no such thing as too many IAL, the darker the water the happier the betta is, you can crush them up in a food processor and make holistic medicines.. Fun fact, the Asian groups who use bettas to fight actually condition their scales with IAL to strengthen them against external injury- while also providing excellent immune systems to ward off infections later from the fights.

^That's amazing, thank you so much for your help. I decided to just switch the betta's over to bottled water. The water from my tap just tested at 8.8 and it takes three weeks of aging to get it down to 7.6. I'm still planning on using IAL, but for its other benefits since I don't want to disrupt the pH too much and would rather put in 7.0 water right away then 7.6, let it go down, then let it go up with another water change. yada yada. And with two tanks totaling up to 5.5 gallons, I can afford a few jugs of water a week.

So I added bottle water to his tank (took out a couple of cups of old water and then topped it off with new) and the pH is down by .2 and is at 7.4, that already seems to be helping, he has even more energy which I didn't think was possible. I also threw in a caffeine free green tea bag last night so that may be helping as well.